Kyoto was the capital of Japan for much of the country's history (794 to 1868). When control of Japan moved from the Shogun to the Emperor in 1868 (after the Boshin civil war) the capital was moved to Tokyo.
Many people in Kyoto still feel that it's the rightful capital. They argue that Kyoto is the "legal capital" of Japan based on numerous technicalities.
Since 1868 Kyoto's power and influence has been in decline. It was once the largest city in Japan. Now it's 7th. Today, Kyoto is a historical city that's popular with tourists from around the globe. It has over 2400 temples and shrines. Many consider it to be the most beautiful city in the World.